Red Sox shortstop Stephen Drew was diagnosed with a concussion 10 days ago after getting beaned in the batting helmet by a pitch. And the 30-year-old has not made a whole lot of tangible progress since.

Scott Lauber — Red Sox beat writer for the Boston Herald — reports that Drew “has been cleared only to lightly play catch, not to take batting practice or ramp up his physical activity.” Which prompted Red Sox manager John Farrell to acknowledge Sunday morning in Fort Myers, Florida that “the window is narrowing” on Drew’s chances of opening the regular season as a member of the active 25-man roster.

Drew has been in contact with Dr. Michael Collins, a concussion specialist at the University of Pittsburgh Medical Center. But no amount of advice or treatment can help curb the symptoms. It’s all about rest.

“This is one of those things that time has got to be given for those symptoms to subside,” Farrell said.

The Red Sox will probably feature Jose Iglesias as their starting shortstop until Drew is ready.

Paxton, 30, has been among the game’s better starters over the past few years. In 2018, he went 11-6 with a 3.76 ERA and a 208/42 K/BB ratio in 160 1/3 innings. The lefty has two more years of arbitration eligibility remaining after earning $4.9 million this past season.

Sheffield, 22, is the headliner in the Mariners’ return. He made his major league debut in September for the Yankees, pitching 2 2/3 innings across three appearances. Two of those appearances were scoreless; in the third, he gave up a three-run home run to J.D. Martinez, certainly not an uncommon result among pitchers. MLB Pipeline rates Sheffield as the Yankees’ No. 1 prospect and No. 31 overall in baseball.

Thompson-Williams, 23, was selected by the Yankees in the fifth round of the 2016 draft. This past season, between Single-A Charleston and High-A Tampa, he hit .299/.363/.546 with 22 home runs, 74 RBI, 63 runs scored, and 20 stolen bases in 415 plate appearances. He was not among the Yankees’ top-30 prospects, per MLB Pipeline.

Swanson, 25, was selected by the Yankees in the eighth round of the 2014 draft. He spent most of his 2018 campaign between Double-A Trenton and Triple-A Scranton/Wilkes-Barre. Overall, he posted a 2.66 ERA with a 139/29 K/BB ratio in 121 2/3 innings. MLB Pipeline rated him No. 22 in the Yankees’ system.

This trade comes as no surprise as the Yankees clearly wanted to upgrade the starting rotation and the Mariners seemed motivated to trade Paxton this offseason. To the Mariners’ credit, they got a solid return for Paxton, as Sheffield likely becomes the organization’s No. 1 prospect. The only worries about this trade for the Yankees is how Paxton will fare in the more hitter-friendly confines of Yankee Stadium compared to the spacious Safeco Field, and Paxton’s durability. Paxton has made more than 20 starts in a season just twice in his career — the last two years (24 and 28). The Yankees are likely not done adding, however. Expect even more new faces before the start of spring training.